Mechanical forces powerfully modulate stem cell fate. Despite the emerging importance of these forces in stem cell differentiation, the molecular mechanisms by which mechanical cues direct cell fate remain unknown. We propose that the stretch-activated ion channels (SACs) transduce mechanical information sensed at the plasma membrane to downstream signaling molecules that control cell fate. In this revised application we will test this hypothesis in light of new preliminary data from our group demonstrating that the recently-identified SAC Piezo1 underlies mechanotransduction currents in human neural stem/progenitor cells and influences neuronal-glial lineage choice. In Aim 1 we will directly test the hypothesis that Piezo1 links mechanical signals to downstream transcription factor activity and mechanosensitive lineage specification. In Aim 2 we will determine whether Piezo1 activity is involved in lineage specification in vivo. Together, the two Aims will establish Piezo1 as a ke signaling molecule in mechanoregulation of human neural stem/progenitor cell fate. In summary, this proposal brings together our expertise in ion channel biophysics, mechanics, biomaterials and stem cell biology to uncover a new molecular player with implications for both, basic stem cell biology and future developments in regenerative medicine.